windows: Add support for non-UTF codepages

Our previous assumption that all paths in Windows are encoded in UTF-8
is rather weak, specially when considering that Git is
encoding-agnostic.

These set of functions allow the user to change the library's active
codepage globally, so it is possible to access paths and files on all
international versions of Windows.

Note that the default encoding here is UTF-8 because we assume that 99%
of all Git repositories will be in UTF-8.

Also, if you use non-ascii characters in paths, anywhere, please burn on
a fire.

6 files changed, 49 insertions, 28 deletions

diff --git a/src/config.c b/src/config.c
index f53afa145..ad6f88575 100644
--- a/src/config.c
+++ b/src/config.c
@@ -370,7 +370,7 @@ static int win32_find_system(char *system_config_path)
 		return GIT_ENOTFOUND;
 	}
 
-	apphome_utf8 = conv_utf16_to_utf8(apphome_utf16);
+	apphome_utf8 = gitwin_from_utf16(apphome_utf16);
 	free(apphome_utf16);
 
 	if (strlen(apphome_utf8) >= GIT_PATH_MAX) {
diff --git a/src/win32/dir.c b/src/win32/dir.c
index ab50318e3..fea74b4eb 100644
--- a/src/win32/dir.c
+++ b/src/win32/dir.c
@@ -6,7 +6,8 @@
  */
 #define GIT__WIN32_NO_WRAP_DIR
 #include "dir.h"
-#include "utf8-conv.h"
+#include "utf-conv.h"
+#include "git2/windows.h"
 
 static int init_filter(char *filter, size_t n, const char *dir)
 {
@@ -43,7 +44,7 @@ git__DIR *git__opendir(const char *dir)
 	}
 	strcpy(new->dir, dir);
 
-	filter_w = conv_utf8_to_utf16(filter);
+	filter_w = gitwin_to_utf16(filter);
 	new->h = FindFirstFileW(filter_w, &new->f);
 	free(filter_w);
 
@@ -73,7 +74,7 @@ struct git__dirent *git__readdir(git__DIR *d)
 		return NULL;
 
 	d->entry.d_ino = 0;
-	WideCharToMultiByte(CP_UTF8, 0, d->f.cFileName, -1, d->entry.d_name, GIT_PATH_MAX, NULL, NULL);
+	WideCharToMultiByte(gitwin_get_codepage(), 0, d->f.cFileName, -1, d->entry.d_name, GIT_PATH_MAX, NULL, NULL);
 
 	return &d->entry;
 }
@@ -90,7 +91,7 @@ void git__rewinddir(git__DIR *d)
 		d->first = 0;
 
 		if (init_filter(filter, sizeof(filter), d->dir)) {
-			filter_w = conv_utf8_to_utf16(filter);
+			filter_w = gitwin_to_utf16(filter);
 			d->h = FindFirstFileW(filter_w, &d->f);
 			free(filter_w);
 
diff --git a/src/win32/posix.h b/src/win32/posix.h
index 442717e42..3774e7883 100644
--- a/src/win32/posix.h
+++ b/src/win32/posix.h
@@ -9,7 +9,7 @@
 
 #include "common.h"
 #include "fnmatch.h"
-#include "utf8-conv.h"
+#include "utf-conv.h"
 
 GIT_INLINE(int) p_link(const char *GIT_UNUSED(old), const char *GIT_UNUSED(new))
 {
@@ -21,7 +21,7 @@ GIT_INLINE(int) p_link(const char *GIT_UNUSED(old), const char *GIT_UNUSED(new))
 
 GIT_INLINE(int) p_mkdir(const char *path, int GIT_UNUSED(mode))
 {
-	wchar_t* buf = conv_utf8_to_utf16(path);
+	wchar_t* buf = gitwin_to_utf16(path);
 	int ret = _wmkdir(buf);
 
 	GIT_UNUSED_ARG(mode)
diff --git a/src/win32/posix_w32.c b/src/win32/posix_w32.c
index cc17cc71f..a05aafcca 100644
--- a/src/win32/posix_w32.c
+++ b/src/win32/posix_w32.c
@@ -6,7 +6,7 @@
  */
 #include "posix.h"
 #include "path.h"
-#include "utf8-conv.h"
+#include "utf-conv.h"
 #include <errno.h>
 #include <io.h>
 #include <fcntl.h>
@@ -17,7 +17,7 @@ int p_unlink(const char *path)
 	int ret = 0;
 	wchar_t* buf;
 
-	buf = conv_utf8_to_utf16(path);
+	buf = gitwin_to_utf16(path);
 	_wchmod(buf, 0666);
 	ret = _wunlink(buf);
 	free(buf);
@@ -59,7 +59,7 @@ GIT_INLINE(time_t) filetime_to_time_t(const FILETIME *ft)
 static int do_lstat(const char *file_name, struct stat *buf)
 {
 	WIN32_FILE_ATTRIBUTE_DATA fdata;
-	wchar_t* fbuf = conv_utf8_to_utf16(file_name);
+	wchar_t* fbuf = gitwin_to_utf16(file_name);
 
 	if (GetFileAttributesExW(fbuf, GetFileExInfoStandard, &fdata)) {
 		int fMode = S_IREAD;
@@ -161,7 +161,7 @@ int p_readlink(const char *link, char *target, size_t target_len)
 				"'GetFinalPathNameByHandleW' is not available in this platform");
 	}
 
-	link_w = conv_utf8_to_utf16(link);
+	link_w = gitwin_to_utf16(link);
 
 	hFile = CreateFileW(link_w,			// file to open
 			GENERIC_READ,			// open for reading
@@ -223,7 +223,7 @@ int p_readlink(const char *link, char *target, size_t target_len)
 int p_open(const char *path, int flags)
 {
 	int fd;
-	wchar_t* buf = conv_utf8_to_utf16(path);
+	wchar_t* buf = gitwin_to_utf16(path);
 	fd = _wopen(buf, flags | _O_BINARY);
 
 	free(buf);
@@ -233,7 +233,7 @@ int p_open(const char *path, int flags)
 int p_creat(const char *path, int mode)
 {
 	int fd;
-	wchar_t* buf = conv_utf8_to_utf16(path);
+	wchar_t* buf = gitwin_to_utf16(path);
 	fd = _wopen(buf, _O_WRONLY | _O_CREAT | _O_TRUNC | _O_BINARY, mode);
 
 	free(buf);
@@ -261,7 +261,7 @@ int p_stat(const char* path, struct stat* buf)
 
 int p_chdir(const char* path)
 {
-	wchar_t* buf = conv_utf8_to_utf16(path);
+	wchar_t* buf = gitwin_to_utf16(path);
 	int ret = _wchdir(buf);
 
 	free(buf);
@@ -270,7 +270,7 @@ int p_chdir(const char* path)
 
 int p_chmod(const char* path, int mode)
 {
-	wchar_t* buf = conv_utf8_to_utf16(path);
+	wchar_t* buf = gitwin_to_utf16(path);
 	int ret = _wchmod(buf, mode);
 
 	free(buf);
@@ -279,7 +279,7 @@ int p_chmod(const char* path, int mode)
 
 int p_rmdir(const char* path)
 {
-	wchar_t* buf = conv_utf8_to_utf16(path);
+	wchar_t* buf = gitwin_to_utf16(path);
 	int ret = _wrmdir(buf);
 
 	free(buf);
@@ -289,7 +289,7 @@ int p_rmdir(const char* path)
 int p_hide_directory__w32(const char *path)
 {
 	int error;
-	wchar_t* buf = conv_utf8_to_utf16(path);
+	wchar_t* buf = gitwin_to_utf16(path);
 
 	error = SetFileAttributesW(buf, FILE_ATTRIBUTE_HIDDEN) != 0 ?
 		GIT_SUCCESS : GIT_ERROR; /* MSDN states a "non zero" value indicates a success */
@@ -305,7 +305,7 @@ int p_hide_directory__w32(const char *path)
 char *p_realpath(const char *orig_path, char *buffer)
 {
 	int ret, alloc = 0;
-	wchar_t* orig_path_w = conv_utf8_to_utf16(orig_path);
+	wchar_t* orig_path_w = gitwin_to_utf16(orig_path);
 	wchar_t* buffer_w = (wchar_t*)git__malloc(GIT_PATH_MAX * sizeof(wchar_t));
 
 	if (buffer == NULL) {
@@ -380,7 +380,7 @@ int p_setenv(const char* name, const char* value, int overwrite)
 
 int p_access(const char* path, int mode)
 {
-	wchar_t *buf = conv_utf8_to_utf16(path);
+	wchar_t *buf = gitwin_to_utf16(path);
 	int ret;
 
 	ret = _waccess(buf, mode);
diff --git a/src/win32/utf8-conv.c b/src/win32/utf-conv.c
index dec6f8e79..cb607839e 100644
--- a/src/win32/utf8-conv.c
+++ b/src/win32/utf-conv.c
@@ -6,9 +6,29 @@
  */
 
 #include "common.h"
-#include "utf8-conv.h"
+#include "utf-conv.h"
 
-wchar_t* conv_utf8_to_utf16(const char* str)
+/*
+ * Default codepage value
+ */
+static int _active_codepage = CP_UTF8;
+
+void gitwin_set_codepage(unsigned int codepage)
+{
+	_active_codepage = codepage;
+}
+
+unsigned int gitwin_get_codepage(void)
+{
+	return _active_codepage;
+}
+
+void gitwin_set_utf8(void)
+{
+	_active_codepage = CP_UTF8;
+}
+
+wchar_t* gitwin_to_utf16(const char* str)
 {
 	wchar_t* ret;
 	int cb;
@@ -29,7 +49,7 @@ wchar_t* conv_utf8_to_utf16(const char* str)
 
 	ret = (wchar_t*)git__malloc(cb);
 
-	if (MultiByteToWideChar(CP_UTF8, 0, str, -1, ret, cb) == 0) {
+	if (MultiByteToWideChar(_active_codepage, 0, str, -1, ret, cb) == 0) {
 		free(ret);
 		ret = NULL;
 	}
@@ -37,7 +57,7 @@ wchar_t* conv_utf8_to_utf16(const char* str)
 	return ret;
 }
 
-char* conv_utf16_to_utf8(const wchar_t* str)
+char* gitwin_from_utf16(const wchar_t* str)
 {
 	char* ret;
 	int cb;
@@ -58,7 +78,7 @@ char* conv_utf16_to_utf8(const wchar_t* str)
 
 	ret = (char*)git__malloc(cb);
 
-	if (WideCharToMultiByte(CP_UTF8, 0, str, -1, ret, cb, NULL, NULL) == 0) {
+	if (WideCharToMultiByte(_active_codepage, 0, str, -1, ret, cb, NULL, NULL) == 0) {
 		free(ret);
 		ret = NULL;
 	}
diff --git a/src/win32/utf8-conv.h b/src/win32/utf-conv.h
index 1967ac3a1..da03e3385 100644
--- a/src/win32/utf8-conv.h
+++ b/src/win32/utf-conv.h
@@ -7,11 +7,11 @@
 
 #include <wchar.h>
 
-#ifndef INCLUDE_git_utf8conv_h__
-#define INCLUDE_git_utf8conv_h__
+#ifndef INCLUDE_git_utfconv_h__
+#define INCLUDE_git_utfconv_h__
 
-wchar_t* conv_utf8_to_utf16(const char* str);
-char* conv_utf16_to_utf8(const wchar_t* str);
+wchar_t* gitwin_to_utf16(const char* str);
+char* gitwin_from_utf16(const wchar_t* str);
 
 #endif